Slide-valve



(N0.M0del.)

, G. W. DE GEOFF.

SLIDE VALVE.

No. 433,853. Patented Aug. 5, 1890.

WITNESSES.

UNITED STATES PATENT OFFICE.

GEORGE IV. DE GROFF, OF BOSTON, MASSACHUSETTS.

SLIDE-VALVE.

SPECIFICATION forming part Of Letters Patent No. 433,853, dated August 5, 1890. Application filed July 13,1888. Serial No, 279,864. (No model.)

To all whom it may concern.-

Be it known that I, GEORGE \V. DE GEOFF, of the city of Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Slide-Valves for Steam-Engines, &c., of which the following is a full, clear, and exact description.

Thepurpose of this invention is to construct the slide-valve arranged in the steam-chest, and, as well known, adapted to be reciprocated on its seat, so as to obviate to a very considerable degree the loss of power required in moving the valve when the machine is in operation, and also otherwise to improve its working, all substantially as hereinafter described.

In the drawings forming part of this specification, Figures 1 and 2 are central longitudinal sections of the slide-valve of this invention and of the steam-chest and pistoncylinder. Fig. 3 is a section, line 3 3, Fig. 1. Fig. 4: is a view of the face of the valve, Fig. 2.

In the drawings, A is the steam-chest.

B is the piston-cylinder, having piston- C and steam-ports b b at its opposite ends and exhaust-port b midway of its length, severally opening to the steam-chest A, and which is adapted at A for admission of steam and at A as a seat for a slide-valve, all as ordinary and well known, and therefore needing no more particular explanation herein.

D is the slide-valve, located in the steamchest A, and, as well known, adapted to be reciprocated on the seat A This valve D in section in the direction of its stroke is of V shape, and each of its legs (1 d has inner and outer faces (1 d respectively meeting each other at more or less acute angles d d and severally forming the front and rear walls of the valve,with a chamber between them closed at its sides (1 but open at (1 opposite the angles (1 d of the walls. The valve at its open side (1" seats on the valve-seat A of the steam-chest, and as to the seat the V-valve is inverted. The open side of the.valve in the direction ofthe valve-stroke is suitable to establish on each stroke of the valve communication between the exhaust-port and one steam-port of the cylinder and at the other steam-port between the piston-cylinder and steam-chest, as well-known in slide-valves.

As shown, Fig. 1, the inverted V-valve at its opposite ends has parallel perpendicular walls D D, knife-edged at top, making part of it. The inner faces of the perpendicular walls D and the outer faces of the inclined walls of the valve are ports D D at each end of the valve, for communication to be made through steam-chambers D D at opposite ends of the valve with the steam-ports of the piston-cylinderand the steam-chest. The perpendicular walls D are necessary and essential to the operation of the valve, as explained, and are only advantageous to the extent that they help protect the valve against the action of the steam to upwardly cant it on its seat, which is more or less liable to occur if the steam is allowed to act laterally directly on the outer faces of the inclined walls of the valve, and more perfectly directs the steam to the open steam-ports of the valve.

As shown, Figs. 2 and at, each inclined end wall of the inverted V-valve at its contactface has a chamber or space c1 to receive live steam on each stroke of the valve and to inclose it at certain portions and to set it free at other portions of the valve-stroke, and thus secure to a greater or less extent pressure of steam on the valve to counterbalance its weight, and the pressure of steam exerted on the valve to press it to its seat and to assist in the lubrication of the valve-seat, all obviously advantageous.

An advantage which comes from the peculiar V shape of the valve may be described as follows: When the steam commences to flow from the steamchest through a partiallyopen port, there is a wedging force applied against the sloping side of the V-shaped projection of the valve which tends to start it in its forward course.

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is

1. The combination, with a steam-chest havinga valve-seat with steam and exhaust ports, of an inverted V slide-valve located in said steam-chest and having inclining end walls with inner and outer faces meeting at acute angles and opposite thereto open and seating on the valve-seat of the steam-chest, substantially as described, for the purpose specified.

2. The combination, with a steam-chest havsteam-chest and having" inclining Walls with inner and outer faces meeting at acute angles 15 and opposite thereto open, and provided with steam chambers or spaces, and seating on the valve-seat of the steam-chest, substantially as described, for the purpose specified.

In testimony whereof I have hereunto set 20 my hand in the presence of two subscribing witnesses.

GEO; WV. DE GEOFF.

Witnesses:

ALBERT W. BROWN, EDWARD HAMILTON. 

